Process of desiccating milk.



F. X. GOVERS.

PROCESS OF DESIGOATING MILK. APPLICATION FILED NOV. 12, 1904.

939,495. Patented Nov. 9, 1909.

3 BHBBTBSHEET 1.

F. X. Gowns.

PROCESS OF DESIOGATING MILK. APPLIOATION FILED NOV. 12, 1904.

Patented Nov. 9,1909.

3 SHEETS-SHEET 2.

314 00m to:

Qgdeks.

9 @omms I dMJW w attouwap P. X. GOVERS, PROCESS OF DESIGOATING MILK.

APPLICATION FILED NOV 12, 1904. 939,495. Patented Nov. 9, 1909.

3 SHEETS-SHEET 3.

. I INVENTOR iwomm bgaowms Altome u FRANCIS GOVEBS, OF OWEGO, NEW YORK.

YROCESS OF DESIGGATING MILK.

Application filed November 12, 1904. Serial No. 232,517.

To all whom it may concern:

Be it known that I, FRANCIS X. Govnns, a citizen of the "United States,residing at Owego, in the county of Tioga and State of New York, haveinvented new and useful Improvements in Processes of Desiccating Milk,of which the following is a specification.

This invention relates to-the treatment of milk for the purpose ofreducing the same to a dry state and has for its objectthe production ofa desiccated milk which contains all the solid ingredients of milk insubstantially their native condition and which upon the addition ofwater will be readily re-' stored to milk which is practically identicalwith the fresh untreated material.

It is essential in the practice of my invention in its bestembodiment toavoid so changing the chemical character of any of the ingredients ofmilk that their solubility in water will be diminished or theirpeptogenic properties, color, smell or taste altered or any change madeinthe milk which will revent the desiccated product from producing, uponthe addition of a suitable amount of water, a milk indistinguishablefrom untreated milk.

It is known that milk contains ingredients which are highly sensitive tothe various agencies of chemical change. .For example, the albumen ofmilk begins to coagulate at a temperature of about 160 F. Between 100and 155 F. the milk sugar is very rapidly changed into lactic acid, therangeof temperature noted being highly favorable to the action offerments. The milk sugar and the proteid constituent of milk are slowlyaltered by the oxygen of the air at a temperature of above about 120 F.producing a deposit or precipitate which ordinarily takes the form of afilm or skin on the surface of the milk and on-the inner walls of thecontaining receptacle. The

proteid constituent of milk loses its p'epto-' genie properties as wellas its property of swelling at a temperature of 212 F.

The efforts of early investigators in the field of milk desiccation werelargely di-' milk sours before it can be concentrated by Specificationof Letters Patent.

Patented Nev. 9,1909.

the methods of evaporation used. In orderto render the concentrationmore rapid, heated air hasbeen blown through the milk during itsevaporation but the oxidizing action of the air on ingredients of themilk not only diminishes their solubility but produces a precipitate ofinsoluble material during the process of concentration. having beenfound to overcome the practical difliculty encountered in the attemptsto produce a soluble milk powder having the pep togenic properties offresh milk, at a relatively low temperature, efforts have been made todesiccate milk at a temperature above 212 on the theory that diminishingthe solubility and peptogenic properties of the milk ingredients is lessdetrimental in milk condensation than the result of the action of theferments and air on the milk at.

No way digestibilityof the milk ingredients'will be as slight aspossible.

I have discovered a process of desiccating milk which is free from thedisadvantage of both the low temperature and the high temperaturemethods and which produces a whole dry condensed milk which is readilysoluble in water producing a milk. practically in istinguishable fromthe fresh milk' and whic is as readily digested as such untreated milk.-

- Inthe practice of my said process whole or skim-milk is first freedfrom some of the water containedtherein by being boiled violently insmall quantities at diminished atmospheric pressure and at a relativelylow temperature and is then rapidly dried by exposure under diminishedatmospheric pressure in a thin film or sheet to a temperaturesufliciently high to rapidly effect the complete desiccation of themilk. 1

In the accompanying drawings is illustrated the apparatus which I preferto employ in carrying out my new process. It will be understood however,that other apparatus may be employed as the process depends in a lessdegree for its successful practise on the form of -apparatus used thanonthe principle of actlon of such apparatus.

'Figure 1, in the drawing, is ail end elevavacuum chamber. Likecharacters of reference designate cor-,

tion showing the pump used to remove air and moisture from within theevaporating or vacuum chamber. Fig. 2 is a longitudinal sectional 'viewon line 22 of Fig. 1 showing the wall of the vacuum chamber cut away andshowing one of the evaporating cylinders and a small quantity of partlydesiccated milk between the cylinders. Fig. 3 is a'transverse sectionalview looking in the direction indicated by the arrow and showingespecially the air excluding trap for removing the desiccated milk fromthe responding parts throughout the several views.

The milk to be desiccated is stored in any convenient reservoir 1 and isconducted into the vacuum chamber 2 through the pipe 3. The flow ofthe'milk through the pipe 3 is controlled by the cock 4:. Within thevacuum chamber 2 are rotatably mounted a pair of hollow metal cylinders5- suitably journaled inaframe-work (3 located without the said chamber2 and provided with suitable stuffing boxes to permit the trunnions topass through the Walls of the chamber without admitting airtherethrough. The cylinders 5 are mounted for rotation by means ofsuitable gearing 7 acting upon the external ends of the trunnions andoperated by a suitable belt 8 from a line shaft 9 or other convenientsource of power. Suitable plates 10 disposed within the vacuum chamberare adapted to bear against the opposite ends of the cylinders 5 and thedegree of pressure of said plates against the cylinders is controlledby-suitable means as the setscrews 11. The cylinders 5 are adapted topractically contact at a point 12, on a line connecting the axes of saidcylinders. The plates 10 bearing against theopposite ends of thecylinders 5 form with the said cylinders, a receptacle 13 to receive andretain a small quantity of the 'milk to be desiccated, as shown at 14.The trunnions of the cylinders 5 are hollow and pipes 15 provided withsuitable stufling boxes pass throughthe hollow trunnion at one end ofthe machine and-within the hollow cylinders 5. Intermediate the ends ofthe cylinders 5 the pipes .15 are provided with depending verticalportions 16 and horizontally disposed portions 17 connected therewithand extending laterally approximately throughout the length of thecylinders. The horizontal portion 17 is provided with a plurality ofopenings 18 formed within the lower side thereof. A pipe 19 is passedthrough a stuffing box within the hollow trunnion at the opposite end ofthe cylinders 5 and is provided with a cock 20. Scrapers 21 are disposedto bear against the cylinder-5 and are suitably secured to the Walls ofthe vacuum chamber2 as by bolts 22.

' To exhaust air and vapor from the vacuum chamber 2, a pump 23 isprovided which may be operated by a crank 24: upon pulley 25, receivingmotion from line shaft 9 by means of belt 26. The pump 23 is connectedwith the vacuum chamber 2 as by pipe 27. A four wing valve 28 within asuitable seat 29 formed in the casing 2 is provided to permit theremoval of the desiccated product from the apparatus without admittingany considerable amount of air to the vacuum chamber. The valve 28 maybe rotated by a crank as 30 located without the vacuum chamber andconnected to the valve by means of shaft 3 passing through the walls ofthe casing and provided with a suitable stufling box.

In carrying out my new process in its preferred embodiment, theatmospheric pressure within the vacuum chamber is reduced until waterwill boil therein at a temperature of about 157 F. and water at asomewhat higher temperature is admitted through pipes 15 into cylinders5, where after passing through openings 18, it comes into contact withthe inner surface of the cylinder walls. When the cylinders 5 havebecome filled with the water, a cock 20 is regulated to permit thepassage of water through the pipe 19 and sufiicient water is passedtherethrough to hold the temperature of the outer surfaces of thecylinders at the desired point preferably between 155 and 165 F. Milk isnow admitted to the receptacle 13 from the storage tank and upon cominginto contact with the hot walls of this receptacle boils violently underthe diminished pressure and a portion of the water is rapidlyevaporated, producing a partially condensed milk, which is thenthoroughly desiccated as hereafter described. Fresh milk is admittedcontinuously as rapidly as the evaporation'of the water takes place, theflow of milk being regulated by the cock 4 in accordance with therapidity of evaporation, which is governed by the degree of vacuum'inthe evaporating chamber and by the temperature of the rolls. It isdesirable to admit the fresh milk to the receptacle 13 at a pointintermediate the ends of the cylinders 5 to limit as much as possiblethe escape of uncondensed milk between the cylinders and the end plates10. The cylinders 55, rotating in the direction indicated by the arrowcarry with them upon their surfaces, a thin film of the partiallycondensed milk which, at the temperature of the cylinder is thoroughlydesiccated under the diminished atmospheric pressure by the time itreaches the scrapers 21. As the milk is taken by the cylinders 5 fromthe narrow lower portion of the receptacle 13, it is obvious that themilk thus withdrawn will be that which is the most com pletely condensedof any of the milk within the receptacle. When the milk reaches thescrapers itis removed by them and falls into the receptacles formed bythe vanes of the four wing valves 28, by the rotation of which valves,it may 'be removed from the vacuum chamber without destroying the vacuumtherein.

In some cases I'may add a small quantity of an alkali or an alkaline oralkaline earthv salt to the milk prior to condensing it, to facilitateits condensation and to improve the character of the product. This isparticularly necessary in the case of milk of excessive or abnormalacidity; when I add suificient of the alkali or salt to make the milkabout neutral. When the addition above mentioned is made, I prefer toemploy a salt which is a normal constituent of milk as potassiumphosphate or calcium citrate.

The dried milk as it comes from the vacuum chamber is in a sterilizedcondition and may be passed directly into cans or other receptacles orit may be compressed into tablets.

' I have found that by my new process it is possible to produce a driedmilk which can e readily reduced to an impalpable powder by any of themeans or processes commonly employed in pulverizing grain, pharmaceu-'tical preparation and the like and I prefer to so reduce my product andto market it in the form of an impalpable'powder.

Having thus described my invention, what I claim as novel and desire tosecure by Letters Patent, is:

1. The process of desiccating milk which consists in rapidly partiallycondensing the same under diminished atmospheric pressure at atemperature below 212 F., withdrawing ortions of the partially condensedmaterial rom below,the surface thereof and subjecting it in thin massesto heat at a temperature below 212 F., under diminished atmosphericpressure.

2. The process of desiccating milk which consists in rapidly same byboiling it violently by exposure, under diminished atmospheric pressure,I to moving heated surfaces, withdrawing the partia 1y condensedmaterial from the bottom of the mass in thin layers or films of uniformthickness upon the said heated surfaces, under. diminished atmosphericpressure.

3. The process of desiccating milk which consists in rapidly partiallycondensing the same by bringing it in small quantities under diminishedatmospheric pressure into contact 'withheated surfaces maintained at atemperature below 212 'F. but sufliciently high to produce almostimmediate violent ebullition of the whole volume of the milk,withdrawing the partially condensed material from the bottom of the massin the form of thin layers or films upon moving rollers and subjectingthe same to heat at a temperature below 212 F., under diminishedatmospheric pressure.

In testimony whereof I aflix my signature,

in presence of two subscribing witnesses.

FRANCIS X. GOVERS.

Witnesses:

'MABTIN E. STINER,

DANIEL J. POTTERTON.

